Host range, purification, and genetic variability in Sweet potato chlorotic fleck virus

Sweet potato chlorotic fleck virus (SPCFV) has recently been classified as a putative new member of the genus Carlavirus (family Flexiviridae) on the basis of its molecular properties. In this study, SPCFV was characterized in terms of host range, physical and biological characteristics, and genetic variability. In addition to sweet potato, SPCFV infected some plant species in the families Convolvulaceae, Chenopodiaceae, and Solanaceae. Limited numbers of virus particles were observed in the assimilation parenchyma cells of infected plant tissues; some cells had a distorted and enlarged endoplasmic reticulum though without any cytoplasmic and amorphous inclusions. The normal length of SPCFV particles was determined to be approximately 800 nm. In enzyme-linked immunosorbent assays, polyclonal antibodies raised against purified SPCFV virions were able to detect the virus in infected sweet potato and indicator plant tissues. In immunoelectron microscopy, SPCFV particles were all strongly decorated when reacted with homologous antiserum. Comparison of the 3′ terminal part of the genome of a range of geographically diverse isolates revealed a high level of genetic diversity. The amino acid sequence identity in the coat protein and the nucleic acid binding protein ranged from 89 to 99.7% and from 75.9 to 99.2%, respectively. Phylogenetic analysis of both proteins showed a geographically associated clustering into two genogroups

Innovating for skills enhancement in agricultural sciences in Africa: The centrality of field attachment programs

Africa remains an intensely agrarian continent, with two-thirds of its people directly or indirectly deriving their livelihood from agriculture. Higher agricultural education has thus emphasised production of graduates with the requisite skills to drive agricultural development. Despite these efforts, too few graduates in sub-Saharan Africa (SSA) have the employable skills necessary to transition to the labour market. A similar situation is observable among agricultural science graduates, who are vital to serving rural smallholder farmers. Most Colleges of Agriculture in Africa offer field attachment internships in agriculture and related fields but they are largely designed to cater for undergraduate students and are not part of the training programs at graduate level. To ameliorate this gap, the Regional Universities Forum for Capacity Building in Agriculture (RUFORUM), a network of 55 member universities in SSA, designed and rolled out an innovative field attachment program award (FAPA), launched in 2010, to serve graduate students. The FAPA is competitively based and designed to encourage students to follow through with the dissemination of their research and to enable them to link more closely with the communities and agencies working in the geographical area where the research was undertaken.During the period 2010–2015, five grant cycles were successfully implemented and 114 graduate students from 17 countries in SSA awarded. This article discusses the lessons learned during this period by examining two key areas: (1) the application process and implementation of the awards; and (2) the reported outcomes and challenges for grantees. Establishing the award has generated key technical and implementation lessons that the network and individual universities have been able to use to improve and institutionalise processes. Grantees have reported gaining a range of cross-cutting skills in personal mastery, initiative leadership and innovativeness, proactivity, flexibility, communication, analytical capacity, teamwork, networking and advocacy, and technical capacity, particularly in engaging with smallholder farmers. They have also noted significant challenges, in particular around establishing productive and sustainable engagement with smallholder farmers. These outcomes have influenced curricular reviews by member universities, with particular emphasis on these skills sets. Keywords: graduate employability, internships, sub-Saharan Africa, university

Nematode distribution and damage to yam in central and eastern Uganda

Yams (Dioscorea spp.) are food crops of growing significance in sub Saharan Africa. Unfortunately, nematodes are major pests to their production. A study was undertaken in major yam growing areas of Uganda to investigate the association of plant parasitic nematodes with damage symptoms. Nematodes were assessed from tubers, roots and surrounding soil for seven cultivars belonging to Dioscorea alata, D. bulbisiana, D. burkilliana and D. cayenensis at harvest. Pratylenchus sudanensis was found in the greatest density and was followed byMeloidogyne spp. Higher densities of both nematodes were observed in the tubers rather than roots. Although symptoms of cracking and galling were relatively low, P. sudanensis incidence was strongly associated with cracking and Meloidogyne spp. with galling. Pratylenchus sudanensis and Meloidogyne spp. incidence their associated damage were, however, negatively correlated, suggesting inter-species competition. Principal components analysis of data suggested that differences in susceptibility to P. sudanensis occur between yam cultivars and species

Scientific data management training

Meeting: For PhD students specializing in Soil and Water Management hosted at Sokoine University of Agriculture in Tanzania (SUA), September 20-23, 2012, Imperial Botanical Entebbe, Kampala UgandaThe training course was funded by Regional Universities Forum for Capacity Building in Agriculture (RUFORUM). RUFORUM organised the three-day hands-on statistics course for targeted postgraduate students involved in soil and water management research. The report provides information on activities and outcomes of the training workshop in Entebbe, Uganda

Linkages with practice for higher-education curriculum innovation

This article is inspired by the debate on curriculum innovation for graduate training, emerging out of linkages between universities and agribusiness development actors, targeting entrepreneurial action and employability of graduates. Experiences from implementation of a three-year joint project are enriched by a desk review, stakeholder feedback and interpretative analysis of process documents during the development of the regional graduate curriculum on Agri-Enterprise Development for Egerton and Gulu Universities in Kenya and Uganda, respectively. The graduate curriculum at the two universities in East Africa integrated the approaches of roundtable engagement and research as well as value chain cluster mapping and development through interactive sharing with agribusiness development facilitators. Simultaneously, the two implementing universities showcased the feasibility of integrating community engagement and entrepreneurial skills into a new curriculum. They achieved this by adopting two training approaches from their previous, more limited curriculum, which lacked student entrepreneurial experiential learning. The outcome from the first cohort of students in the innovative programs demonstrates significant institutional change in teaching and learning approaches. These changes prioritize a blend of action research and theoretical exposure. At the university-wide level, a student-centered teaching and learning approach has been established, facilitated by models like Student Farm Attachment, Student Enterprise Scheme, and Student Community Engagement. Additionally, university-based research teams have honed their skills in community action research, leading to the identification of relevant challenges and plausible solutions. Furthermore, students’ skills sets have increasingly enhanced employability. Strengthening linkages between universities and community development actors can enhance curriculum orientation toward problem-solving and entrepreneurial capacity building for young graduates. Purposeful engagement with communities by university faculty and students serves as a complementary extension approach and advisory service. Implementing an innovative curriculum has the potential to boost research uptake and foster innovation. This article demonstrates how university- industrial actors’ collaboration can be exploited for curriculum (re)design, review and up-dating for (a) enhanced relevance of universities to community needs and employability of graduates; and (b) improvements in the research uptake pathways that facilitate research-into-use for desired impacts at community level

DYNAMICS OF Cercospora zeina POPULATIONS IN MAIZE-BASED AGRO-ECOLOGIES OF UGANDA

Stability of pathogen populations characterised by slow temporal variation is important for durability of disease management systems in any agroecology. Temporal variation in population structure is attributed to factors related to ecology, biology and life history, and varies among organisms and ecosystems. The objective of this study was to investigate genetic variability of Cercospora zeina (previously called Cercospora zeae-maydis Type II) populations in maize ( Zea mays ) producing areas under Uganda conditions. Populations of the fungus were analysed for genetic variability using a fluorescent amplified fragment length polymorphism (AFLP) technique. Little or no genetic differentiation (\u3a6FST 0.05) was detected for populations sampled within the same year, within an agroecology. However, a weak to moderate population structure was detected between populations from different locations, within the same (\u3a6FST = 0.08) or different agroecologies (\u3a6FST = 0.09). Pair-wise comparisons using \u3a6FST gene diversity and genetic distance, showed a reduction in genetic diversity in younger populations, suggestive of minor effects of selection and genetic drift. Overall, the data suggest that during the 3 years of study the impact of selection and genetic drift on C. zeina populations in the two Ugandan agroecologies is slow, but progressive leading to homogenetity with agroecologies and differences between agroecologies.La stabilit\ue9 des populations d\u2019agents pathog\ue8nes caract\ue9ris\ue9e par une faible variation dans le temps, est importante pour la durabilit\ue9 dans les syst\ue8mes de gestion des pathologies des plantes dans n\u2019importe quelle zone agro-\ue9cologique. La variation dans le temps au sein d\u2019une population, est fonction de facteurs relatifs \ue0 l\u2019\ue9cologie, la biologie et l\u2019histoire de vie des pathog\ue8nes. Elle varie d\u2019un \ueatre vivant \ue0 un autre et d\u2019un \ue9cosyst\ue8me \ue0 un autre. L\u2019objectif de cette \ue9tude \ue9tait d\u2019\ue9valuer la variabilit\ue9 g\ue9n\ue9tique au sein des populations de Cercospora zeina (pr\ue9cedemment appel\ue9 Cercospora zeae-maydis Type II) dans les zones productrice de ma\uefs ( Zea mays ) en Ouganda. Les populations de ce champignon microscopique ont \ue9t\ue9 soumises \ue0 une \ue9tude de variabilit\ue9 g\ue9n\ue9tique gr\ue2ce \ue0 la technique du polymorphisme de longueur de fragments amplifi\ue9s (AFLP). Tr\ue8s peu ou aucune variation g\ue9n\ue9tique (\u3a6FST 0.05) n\u2019a \ue9t\ue9 observ\ue9e pour les populations \ue9chantillonn\ue9es au cours de la m\ueame ann\ue9e, dans une zone agro-\ue9cologique donn\ue9e. N\ue9anmoins, une structure populationnelle d\u2019envergure faible \ue0 mod\ue9r\ue9e a \ue9t\ue9 observ\ue9e entre les populations de diff\ue9rentes origines, (\u3a6FST = 0.08) \ue0 l\u2019int\ue9rieur d\u2019une m\ueame population ou (\u3a6FST = 0.09) entre les populations de diff\ue9rente zones agro \ue9cologique. La comparaison par paires utilisant \u3a6FST diversit\ue9 des g\ue8nes et distance g\ue9n\ue9tique, a montr\ue9 une r\ue9duction de diversit\ue9 g\ue9n\ue9tique dans les populations les plus jeunes, sugg\ue9rant ainsi un effet mineur de s\ue9lection et de d\ue9rive g\ue9n\ue9tique. Au total, les donn\ue9es collect\ue9es indiquent un faible impact de s\ue9lection et de d\ue9rive g\ue9n\ue9tique sur les populations de C. zeina dans les deux zones agro-\ue9cologiques Ougandaise durant les 3 ann\ue9es de l\u2019\ue9tude, mais cet impact est progressif et responsable de l\u2019homog\ue9n\ue9it\ue9 au sein des zones agro-\ue9cologiques et des diff\ue9rences entre les zones agro-\ue9cologiques

INHERITANCE OF ROOT DRY MATTER CONTENT IN SWEETPOTATO

There has been much emphasis on breeding for increased sweetpotato storage root yield, but less on dry matter yield, and its inheritance. High dry matter content (DMC) is associated with consumer preferences, and is important for the processing industry. This study was conducted to determine the type of gene action controlling DMC and to assess genotype by environment (G x E) interaction effect on DMC in sweetpotato. Five parental clones varying in DMC were hand-crossed in a half-diallel design to generate ten families. Ten genotypes of each family were planted in a trial at Namulonge (swamp and upland environments) and Serere in Uganda in 2009 and 2010. Highly significant (P<0.001) differences were found both between genotypes and between families for DMC. High significant general combining ability (GCA) (P<0.001) and specific combining ability (SCA) (P<0.01) were obtained, meaning that the differences among families for high DMC were due to both GCA and SCA. The relative importance of GCA and SCA was 0.59, indicating that additive gene action was slightly more predominant than non-additive gene action in predicting progeny performance for high DMC. Broad sense heritability (H) estimates for DMC were 0.70 and 0.73, respectively on genotype and family means across environments basis, suggesting that DMC was moderately influenced by the environment. Rapid selection for best genotypes would be possible, since progenies can be predicted from the phenotype of the parents. Parent SPK (GCA = 1.02) was the best combiner. The effect of location was less significant compared to seasons, suggesting the need to evaluate genotypes for several seasons, but in few locations to save resources.Plusieurs efforts ont \ue9t\ue9 fournis dans le cadre d\u2019augmenter le rendement de la patate douce, mais peu d\u2019efforts visant le rendement sec et son h\ue9ritabilit\ue9. La mati\ue8re s\ue8che est associ\ue9e aux pr\ue9f\ue9rences des consommateurs et elle est importante dans l\u2019industrie de transformation. Cette \ue9tude a \ue9t\ue9 men\ue9e dans le but de d\ue9terminer le type de l\u2019action g\ue9n\ue9tique contr\uf4lant la mati\ue8re s\ue8che, ainsi que d\u2019\ue9valuer l\u2019effet d\u2019interaction g\ue9notype x environnement sur la mati\ue8re s\ue8che sur la patate douce. Cinq diff\ue9rents parents en terme de mati\ue8re s\ue8che ont \ue9t\ue9 crois\ue9s en moiti\ue9 diall\ue8le et dix familles sont obtenues. Les semences sont plant\ue9es dans les boites en bois dans les serres \ue0 Namulonge, Uganda. Dix g\ue9notypes pour chacune des familles sont plant\ue9es dans l\u2019essai \ue0 Namulonge (environnement marrais et hautes terres) et Serere en bloques compl\ue8tement randomis\ue9es, avec deux r\ue9p\ue9titions, durant la p\ue9riode Octobre 2009-Mars 2010. Pour d\ue9terminer la mati\ue8re s\ue8che, une quantit\ue9 de 200 g pour chacune des g\ue9notypes a \ue9t\ue9 s\ue9ch\ue9e \ue0 650C jusqu\u2019\ue0 ce que le poids soit constant. Les donn\ue9es sont analys\ue9es en utilisant le logiciel Genstat. Aptitude g\ue9n\ue9rale \ue0 la combinaison (AGC) et aptitude sp\ue9cifique \ue0 la combinaison (ASC) sont calcul\ue9es selon Mod\ue8le I, M\ue9thode 4 selon la description de Griffing (1956). Hautes significative (P< 0,001) diff\ue9rences sont trouv\ue9es aussi bien entre g\ue9notypes que familles pour la mati\ue8re s\ue8che. Hautes significatives AGC (P<0,001) et ASC (P<0,01) sont trouv\ue9es, signifiant que les diff\ue9rences observ\ue9es entre les familles pour la mati\ue8re s\ue8che sont dues \ue0 la fois \ue0 AGC et ASC. L\u2019importance relative de l\u2019AGC et ASC \ue9tait 0,59, ce qui indique que l\u2019action g\ue9n\ue9tique additive \ue9tait un peu plus importante que l\u2019action g\ue9n\ue9tique non-additive en pr\ue9dicant la performance des prog\ue9nitures pour la mati\ue8re s\ue8che. L\u2019h\ue9ritabilit\ue9 en large sens (H) pour la mati\ue8re s\ue8che \ue9tait de 0,70 et 0,73 en se basant respectivement sur la moyenne du g\ue9notype et celle de la famille sur tous les environnements, sugg\ue9rant que la mati\ue8re s\ue8che \ue9tait mod\ue9r\ue9ment influenc\ue9e par l\u2019environnement. Ceci indique que la s\ue9lection rapide des g\ue9notypes serait possible, car les prog\ue9nitures peuvent \ueatre pr\ue9venues en se basant sur le ph\ue9notype des parents. Parent SPK (GCA=1,02) \ue9tait la meilleure combinant dans cette \ue9tude. L\u2019effet des locations \ue9tait moins significatif comparable aux saisons, sugg\ue9rant l\u2019importance d\u2019\ue9valuer les g\ue9notypes sur plusieurs saisons, mais dans les moins de locations dans le cadre d\u2019\ue9conomiser les ressources

Stability of sweet potato cultivars to Alternaria leaf and stem blight disease

Alternaria leaf petiole and stem blight is an economically important disease of sweet potato (Ipomoea batatus L.) in tropical and sub-tropical environments. Published research on cultivar resistance to the sweet potato disease is limited. To evaluate cultivar reaction and stability to the disease, multi-location and replicated experiments were established in 12 environments in Uganda. Disease severity (area under disease progress curves - AUDPC), and cultivar root yield were also assessed. Significant differences (P<0.001) in AUDPC were detected among cultivars. Mean AUDPC ranged from 46.3 (Araka Red) to 78.4 (New Kawogo) across locations and seasons and the genotypes Araka Red and Tanzania had the lowest disease values. The location and season effects accounted for 67.1% and 7.5% of the total variance of AUDPC recorded among cultivars. The ranking of cultivars based on predicted AUDPC from Additive Main Effect and Multiplicative Interactive model (AMMI) showed that the NASPOT 1, the susceptible check, and New Kawogo were most susceptible to the disease in 11 of the 12 environments. Low and stable disease was consistently recorded and predicted on NASPOT 3 and the landrace cultivars Tanzania, Dimbuca, and Araka Red across environments. These results suggest that landrace cultivars had relative stability to the disease and wide adaptation across environments. These results suggest that AMMI statistical model and other multivariate techniques can be utilized for prediction of Alternaria disease stability in these locations